Erin Schrode didn’t know much about the extreme right before she ran for Congress. “I’m not going to tell you I thought anti-Semitism was dead, but I had never personally been the subject of it,” she says.

That changed when The Daily Stormer, a prominent neo-Nazi website, posted an article about her 2016 campaign. The comments section filled up with derogatory statements targeting Schrode because she is Jewish. But buried between slurs and racist images, one anonymous person—under the username “Forbesmag”—posted Schrode’s email address, cell phone number, and links to her social media profiles….